This function blinks an LED light as many times as requested, at the requested blinking rate.
void blinkLED(byte targetPin, int numBlinks, int blinkRate) {
for (int i=0; i < numBlinks; i++) {
digitalWrite(targetPin, HIGH);
delay(blinkRate);
digitalWrite(targetPin, LOW);
delay(blinkRate);
}
}
Blinking a Number
Back in the dawn age of computing sometimes things went wrong enough that the only way to communicate an error to the user was to blink a light. When dealing with micro-controllers this can sometimes come in handy. The following function blinks a sequence to indicate a number visually.
void blinkNumber(char* numString) {
int versLength = strlen(numString);
delay(200);
for (int i =0 ; i < versLength; i++) {
int number = numString -48;
if (number == 0){
blinkLED(LED_A,1,20);
delay(160);
}
if (number > 0 && number < 10) blinkLED(LED_A,number,200);
delay(400);
}
}
Buzzing a Buzzer
A generalised generalised function to make use of Piezo buzzers without having to think through the math each time you want to hear a particular sound frequency. All you need to do is tell the function which pin you’d like to use, the frequency you want to hear, and the duration to play that frequency.
void buzz(int targetPin, long frequency, long length) {
long delayValue = 1000000/frequency/2;
long numCycles = frequency * length/ 1000;
for (long i=0; i < numCycles; i++){
digitalWrite(targetPin,HIGH);
delayMicroseconds(delayValue);
digitalWrite(targetPin,LOW);
delayMicroseconds(delayValue);
}
}
Checking Free RAM
The ATmega328 has 32K of program memory but only 2K of SRAM. Program memory is for code and RAM is for dynamic variables. Actually it’s effectively less than 2K of RAM, because the Arduino libraries will take up some dynamic memory space for themselves.
The Arduino environment will happily let you compile a program that exceeds the micro-controller’s SRAM limits, however program behavior will become totally unpredictable, the code will do bizarre things and/or crash. This function will return the number of bytes currently free in SRAM.
The new Arduino WiFi shield is a pretty nice board. However dealing with different types of network can be troublesome. The following code snippet, will attempt to connect to a WPA/WPA2 encrypted WiFi network whose SSID is stored in the ssid variable, and password stored in the pass variable. However if it can’t find that network it will fall back and scan for open WiFi networks instead.
if (WiFi.status() == WL_NO_SHIELD) {
Serial.println("WiFi shield not present");
while(true);
}
if ( stringFromCharString(ssid) != "" ) {
while ( status != WL_CONNECTED) {
timesWeTriedToConnect++;
Serial.print(F("Attempting to connect to SSID (attempt "));
Serial.print( timesWeTriedToConnect );
Serial.print(F(" of 5): "));
Serial.println(ssid);
status = WiFi.begin(ssid, pass); // Connect to WPA/WPA2 network.
delay(2000);
if ( timesWeTriedToConnect >= 5 ) break;
}
}
if ( status != WL_CONNECTED ) {
Serial.print("Unable to connect to ssid '");
Serial.print( ssid );
Serial.println( "'");
Serial.println("** Scanning for open networks **");
byte numSsid = WiFi.scanNetworks();
Serial.print("number of available networks:");
Serial.println(numSsid);
for (int thisNet = 0; thisNet<numSsid; thisNet++) {
Serial.print(thisNet);
Serial.print(") ");
Serial.print(WiFi.SSID(thisNet));
Serial.print("\tSignal: ");
Serial.print(WiFi.RSSI(thisNet));
Serial.print(" dBm");
Serial.print("\tEncryption: ");
Serial.println(WiFi.encryptionType(thisNet));
if ( WiFi.encryptionType(thisNet) == 7 ) {
Serial.println( "Attempting to connect to open network...");
status = WiFi.begin( WiFi.SSID(thisNet));
delay(10000);
if( status == WL_CONNECTED ) break;
}
}
}
if ( status != WL_CONNECTED ) {
Serial.println( "Unable to connect to network" );
// don't continue:
while(true);
}
Reading and Writing to the EEPROM
Sometimes it can be useful to store numbers, or other data, into the Arduino’s EEPROM to protect it against power-cycling. Using the included EEPROM library it’s actually pretty easy to write a number to EEPROM,
void setNumber(unsigned long ctr) {
Serial.print("Setting number in EEPROM to = ");
Serial.println( ctr );
EEPROM.write(4,(ctr & 0xFFFFFFFF) >> 24); // write the MSB
EEPROM.write(3,(ctr & 0xFFFFFF) >> 16); // write the 3rdB
EEPROM.write(2,(ctr & 0xFFFF) >> 8); // write the 2ndB
www.pighixxx.com/en/ Very nice site, unfortunately they have not converted everything to English yet, so to find the pinout diagrams you must select Italian as the language.
Last Edit: Dec 31, 2013 11:28:19 GMT -5 by BeeAmaker
Some things are meant to be closed. Your mind isn't one of them.
Program a Yún without writing code! Temboo’s Sketch Builder
Choose your sensor, choose what action you want it to trigger, and voila–your Arduino Yún is doing it. Sending texts when a light sensor detects night, logging temperature data to a Google spreadsheet while you’re away, calling you when it sees an intruder in your home.
Context Tutorial 01 for Arduino: Getting Acquainted with Arduino Tutorial 02 for Arduino: Buttons, PWM, and Functions Tutorial 03 for Arduino: Electrical Engineering Basics Tutorial 04 for Arduino: Analog Inputs Tutorial 05 for Arduino: Motors and Transistors Tutorial 06 for Arduino: Serial Communication and Processing Tutorial 07 for Arduino: I2C and Processing Tutorial 08 for Arduino: SPI Interfaces Tutorial 09 for Arduino: Wireless Communication Tutorial 10 for Arduino: Interrupts and Hardware Debouncing Tutorial 11 for Arduino: SD Cards and Datalogging Tutorial 12 for Arduino: RFID Card Reading Tutorial 13 for Arduino: Liquid Crystal Displays Tutorial 14 for Arduino: Holiday Lights and Sounds Tutorial 15 for Arduino: GPS Tracking
These would be a good set of tutorials for us to follow when we do the Arduino class.
Last Edit: Sept 17, 2014 19:57:20 GMT -5 by BeeAmaker
Some things are meant to be closed. Your mind isn't one of them.
